Improvement in coverings for steam-boilers



UNITED STATES PATENT OFFIC MOSES A. JOHNSON, OF LOWELL, MASSACHUSETTS.

IMPROVEMENT IN COl/ERINGS FOR STEAM-BOILERS.

Specification forming part of Letters Patent No. 37,967, dated March 21, 1863.

which it maybe applied, and renders it a better nouconductor of heat and protection against combustion, thereby enablinga felt of less thickness to be used than would otherwise be required.

.For impregnating the felt I use the silicate solution in a weak form and rub it in by the actiou'ot' a filter; ,but for coating it I employ a strong solution, which may be applied with a brush or by other means, like a varnish, to oncor both sides, particularly to the side which is to be applied next the boiler or other heated surface. The surfaces may be afterward washed with a solution of chloride of calcium to prevent efllorescence from the action of the atmosphere, it'under any conditions that may be found necessary.

For some purposes it may be necessary only to impregnate the felt, and for others only to coat it with the solution; but generally it may with advantage be both impregnated and coated.

Otherincombustihleand non conductingSuhstancessoapstone dust, for instancemay be mixed with the silicate-of-soda solution;

What I-claim as my invention, and desire to secure by Letters Patent, is--- v The impregnation and coating of felt with silicate of soda, substantially as and for the purpose herein specified.

Mosns A, JOHNSON. Witnesses:

- HORACE B.-SHA'1TUGK,

GEo. (J. ASHBY. 

